Evaluation of synergistic activity of bovine lactoferricin with antibiotics in corneal infection.

Abstract

OBJECTIVES:

The objectives of this study were to determine whether a synergistic effect could be obtained in vitro between bovine lactoferricin (B-LFcin) and antibiotics against Pseudomonas aeruginosa and Staphylococcus aureus isolates from ocular infections, and to evaluate the use of B-LFcin as an adjunct to the antibiotic treatment of corneal infection in vivo.

METHODS:

Chequerboard and time-kill assays were performed to investigate the combined effects of B-LFcin and conventional antibiotics, including ciprofloxacin, ceftazidime and gentamicin, against 17 strains of P. aeruginosa (8) and S. aureus (9) isolated from ocular infection and inflammation, and 1 reference strain of S. aureus. Corneas of C57BL/6 mice were topically challenged with a multidrug-resistant strain of P. aeruginosa. Nine hours post-challenge, mice were treated topically and hourly with either vehicle, B-LFcin, ciprofloxacin or ciprofloxacin containing B-LFcin for 8 h. Corneas were then clinically examined, and bacterial numbers and levels of myeloperoxidase (MPO) evaluated.

RESULTS:

Synergy between B-LFcin and ciprofloxacin or ceftazidime was identified in most P. aeruginosa isolates, including multidrug-resistant strains, whereas no synergistic effect was seen between B-LFcin and gentamicin. Synergy was only observed with B-LFcin and ciprofloxacin against 2/10 S. aureus strains, and there was no synergy between B-LFcin and any of the other antibiotics tested. Combined B-LFcin and ciprofloxacin treatment significantly improved the clinical outcome, and reduced bacterial numbers and MPO in infected mouse corneas. B-LFcin alone was also able to reduce levels of MPO in infected corneas.

CONCLUSIONS:

These findings indicate that B-LFcin may have advantages as an adjunct therapy with both antimicrobial and anti-inflammatory properties in the treatment of corneal infection.

• Authors: Thein Zaw Oo, Nerida Cole, Linda Garthwaite, Mark D P Willcox, Hua Zhu
• Journal: The Journal of antimicrobial chemotherapy (J Antimicrob Chemother) Vol. 65 Issue 6 Pg. 1243-51 (Jun 2010) ISSN: 1460-2091 [Electronic] England
• PMID: 20375033 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Bacterial Agents
• lactoferricin B
• Lactoferrin

Topics

• Administration, Topical
• Animals
• Anti-Bacterial Agents (administration & dosage, pharmacology)
• Cattle
• Corneal Diseases (drug therapy, microbiology)
• Drug Synergism
• Lactoferrin (administration & dosage, pharmacology)
• Mice
• Mice, Inbred C57BL
• Microbial Sensitivity Tests
• Microbial Viability (drug effects)
• Pseudomonas Infections (drug therapy, microbiology)
• Pseudomonas aeruginosa (drug effects, isolation & purification)
• Staphylococcal Infections (drug therapy, microbiology)
• Staphylococcus aureus (drug effects, isolation & purification)
• Treatment Outcome